1. Field
The present application relates to an image processing apparatus, an imaging apparatus, a computer readable storage medium storing an image processing program, and an image processing method performing processing on a RAW image (image before performing color interpolation) obtained by a color image sensor of single panel type.
2. Description of the Related Art
Conventionally, noise reduction processing through smoothing performed by a digital camera, an image processing software and the like is generally performed on a color-interpolated image, not on a RAW image (refer to Japanese Unexamined Patent Application Publication No. H06-14189, Japanese Patent No. 3689607, Japanese Unexamined Patent Application Publication No. 2009-10823, and the like).
Further, although not disclosed in these documents, a technique for performing noise reduction processing on respective color components of a RAW image has already been proposed.
Normally, in a process of color interpolation processing, a brightness and a color difference of each pixel are made known, so that it is possible to perform aggressive noise reduction processing on a color-interpolated image without blurring an edge of a structure included in the image, but, since the color-interpolated image has a large number of pixels, a calculation amount required for the noise reduction processing becomes enormous.
Meanwhile, since a RAW image has a small number of pixels, it is possible to perform the noise reduction processing on the RAW image with a small calculation amount, but, a brightness and a color difference of each pixel are not separated before performing the color interpolation, so that when an edge of a structure included in the image is tried to be maintained, too aggressive noise reduction processing cannot be performed.